Electromagnetic actuator

Patent metadata

Field	Value
Publication number	US-10692637-B2
Application number	US-201815936367-A
Country	US
Kind code	B2
Filing date	Mar 26, 2018
Priority date	Mar 27, 2017
Publication date	Jun 23, 2020
Grant date	Jun 23, 2020

Abstract

The present invention concerns an electromagnetic actuator for a haptic display. The actuator comprises: a) a first, movable permanent magnetic element, the first magnetic element comprising a first latching layer facing side, a second latching layer facing side substantially opposite to the first latching layer facing side, and at least one lateral face between the first latching layer facing side and the second latching layer facing side; b) a shielding element for shielding laterally the first magnetic element to confine a magnetic field generated by the first magnetic element; c) a first actuation inductor facing the first latching layer facing side for actuating the first magnetic element and arranged to displace the first magnetic element from a first latching position to a second latching position, or vice versa; d) a first latching layer facing the first latching layer facing side and arranged to attract the first magnetic element for obtaining the first latching position; and e) a second latching layer facing the second latching layer facing side and arranged to attract the first magnetic element for obtaining the second latching position, different from the first latching position.

First claim

The invention claimed is:

1. An electromagnetic actuator for a haptic display, the actuator comprising:
a first, movable permanent magnetic element, the first magnetic element comprising a first latching layer facing side, a second latching layer facing side substantially opposite to the first latching layer facing side, and at least one lateral face between the first latching layer facing side and the second latching layer facing side;
a shielding element for shielding laterally the first magnetic element to confine a magnetic field generated by the first magnetic element, the first magnetic element and the shielding element being located concentrically with respect to each other;
a first actuation inductor facing the first latching layer facing side for actuating the first magnetic element and arranged to displace the first magnetic element from a first position, referred to hereinafter as a first latching position, to a second position, referred to hereinafter as a second latching position, or vice versa;
a first latching layer facing the first latching layer facing side and arranged to attract the first magnetic element for obtaining the first latching position of the first magnetic element; and
a second latching layer facing the second latching layer facing side and arranged to attract the first magnetic element for obtaining the second latching position of the first magnetic element, different from the first latching position,
wherein the shielding element is arranged to move together with the first magnetic element when the first magnetic element is actuated.

2. The electromagnetic actuator according to claim 1 , wherein the actuator further comprises a second actuation inductor facing the second latching layer facing side for actuating the first magnetic element and arranged to displace the first magnetic element from the first latching position to the second latching position, or vice versa.

3. The electromagnetic actuator according to claim 2 , wherein the first actuation inductor is located in a first circuit board located between the first magnetic element and the first latching layer, while the second actuation inductor is located in a second circuit board located between the first magnetic element and the second latching layer.

4. The electromagnetic actuator according to claim 1 , wherein the first and/or second actuator inductors are planar single layer or multilayer coils.

5. The electromagnetic actuator according to claim 1 , wherein the shielding element comprises soft magnetic material and is located laterally around the first magnetic element.

6. The electromagnetic actuator according to claim 1 , wherein shielding element comprises a permanent magnet and is located laterally around the first magnetic element, and wherein the first magnetic element and the shielding element have opposite magnetic polarizations.

7. The electromagnetic actuator according to claim 1 , wherein the shielding element comprises soft magnetic material and is arranged to be laterally enclosed by the first magnetic element.

8. The electromagnetic actuator according to claim 1 , wherein the first latching layer and/or the second latching layer comprise(s) soft magnetic material or permanent magnetic material.

9. The electromagnetic actuator according to claim 1 , wherein the height of the first magnetic element is substantially the same as the height of the shielding element.

10. An electromagnetic actuator system comprising the electromagnetic actuator according to claim 1 and further comprising a pin connected to the first magnetic element and arranged to be displaced by the first magnetic element when the first magnetic element is actuated such that the pin is arranged to protrude from a surface to allow it to be tactually sensed by a user of the system.

11. The electromagnetic actuator system according to claim 10 , wherein the system further comprises a sensor for measuring an input from the user when the user is urging the pin.

12. A haptic display comprising:
the electromagnetic actuator system according to claim 10 ; and
an array of said electromagnetic actuators.

13. A method of operating the electromagnetic actuator according to claim 1 , wherein the method comprises:
feeding a current pulse through the first actuation inductor for displacing the first magnetic element from the first latching position to the second latching position or vice versa; and
cutting off the current consumption for a latching duration when the first magnetic element has reached the first or second latching position.

Assignees

• Ecole Polytechnique Fed Lausanne Epfl
• Ecole Plytechnique Fed De Lausanne Epfl

Inventors

• Zarate Juan José
• Shea Herbert

Classifications

• H01F27/366 Primary

  made of ferromagnetic material · CPC title

• H01F2007/1669

  Armatures actuated by current pulse, e.g. bistable actuators · CPC title

• G09B21/004

  Details of particular tactile cells, e.g. electro-mechanical or mechanical layout · CPC title

• H01F7/064

  Circuit arrangements for actuating electromagnets (circuit arrangements for obtaining special operating characteristics H01F7/18; driving circuits for electromagnets making use of a switching regulator H01H47/325) · CPC title

• G06F3/016

  Input arrangements with force or tactile feedback as computer generated output to the user · CPC title